title: Magnetic resonance imaging assessment of tibial tuberosity-trochlear groove distance: normal values for males and females.
abstract: OBJECTIVE
  The aim of this study was to report normal values of the tibial tuberosity-trochlear groove distance (TTTG) in males and females and assess the reliability of MRI in measuring TTTG.
  
  
  METHODS
  Patients presenting with a suspected meniscus injury without any patellofemoral or ligamentous instability, and arthroscopically normal cruciate ligaments and patellofemoral joints were included in the study. K-PACS© was used for MRI analysis and was performed by three observers blinded to each others' measurements.
  
  
  RESULTS
  One hundred patients (57 males, 43 females) were recruited from 2006-2010. The mean TTTG in males was 9.91 mm (95% CI 8.9-10.8 mm) and in females 10.04 mm (95% CI 8.9-11.1). The coefficient of variation was <10% for both intra and inter-observer analysis.
  
  
  CONCLUSIONS
  The normal TTTG distance is 10 ± 1 mm with MRI being a reliable method of measurement. Literature supports a high degree of variability in reporting TTTG. This study establishes normal TTTG values, which will help in the assessment and treatment of patellofemoral disorders.
authors.affiliation: Orthopaedic Surgery, Taranaki Base Hospital, New Plymouth, New Zealand. panditsalil@hotmail.com
authors.forename: Salil
authors.initials: S
authors.lastname: Pandit
authors.forename: Chris
authors.initials: C
authors.lastname: Frampton
authors.forename: Julian
authors.initials: J
authors.lastname: Stoddart
authors.forename: Tim
authors.initials: T
authors.lastname: Lynskey
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D012016:Reference Values; D013977:Tibia / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed